Abstract

We study the frequency autocorrelation of the differential group delay
(DGD) in fibers with polarization mode dispersion (PMD). We show that the correlation bandwidth of the DGD is comparable with that of the orientation of the PMD vector. Furthermore, we show that all the most general statistical properties of polarization mode dispersion in long fibers are uniquely determined by the mean DGD. An estimate of the accuracy of measurements in which the mean DGD is extracted by frequency averaging in a single fiber is obtained as a function of the measured bandwidth.

Figures (2)

(a) Autocorrelation function of the square DGD [Eq. (4)]
as well as results of a Monte Carlo simulation of a fiber with 1000 independent sections (squares). (b) Auto-correlations of the DGD (thin curve) and of the PMD angle (thick curve). The vector autocorrelation is also shown for comparison (dashed curve). The curves were all normalized to their peak values.

(a) Normalized autocorrelation functions of DGD (dots) and of the square DGD (squares). To emphasize the resemblence we show the curves on a logarithmic scale. (b)
Variance of the measured mean DGD when it is frequency averaged over an angular frequency bandwidth of B and divided by τdgd2. The dashed curve corresponds to the asymptotic dependence VarτB≈1.34τdgd/B.